Dissertations / Theses on the topic 'Multiple output'
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Kanday, Balaji Madapuci. "Microcontroller Based Multiple-Input Multiple-Output Transmitter." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/605952.
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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, CaliforniaThis paper describes how a microcontroller based system can be used to generate the signals needed in a multiple-input multiple-output (MIMO) system transmitter. The limited computational speed of the microcontroller, along with other tasks which the controller may need to handle, places limits on the throughput of the system, and the complexity of the MIMO signal design. However this can be a low cost design, and the microcontroller can be used to perform other operations in the system, which may make it attractive in some applications.
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Tran, Tuan-Anh. "Multiple-input multiple-output optical wireless communications." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:094fbe23-88c3-49c4-b64b-a1de40674123.
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Visible-light optical wireless communications (OWC) is a potential technology that can help resolve the crowdedness of the radio-frequency bands, whilst conveniently exploiting energy-saving light-emitting diodes (LEDs) as transmitters for both illumination and communications. Since there usually are many LEDs in a lighting unit, OWC has a multi- input multi-output (MIMO) geometry which, thanks to its channel diversity, can offer wireless local networks at data-rates many times higher than possible with single-channel systems. In such systems, MIMO-detection methods to separate the different optical channels play an important role in improving the system performance by helping reduce cross-talk between channels. To measure the performance of a particular geometry for MIMO communications, a simulation study, reported in this thesis, found that, amongst the signal- independent metrics, the condition number may be used as a rough predictor of the performance, whilst the channel Signal-to-Interference-and-Noise Ratio (SINR) is the most appropriate for geometry assessment. Combined with the fact that the overall performance of a MIMO system is mostly dominated by its worst channel, this indicates that the most effective way to improve the system performance is to maximise the worst channel’s SINR. One of the possible solutions to improving the SINRs is to use holograms to steer the transmitter images such that their distributions over the photo-detectors reduce overlaps. As LEDs emit partially-coherent light, the beam steering has to be carried out with partially- coherent illumination. By using two lenses to parallelise and collect partially-coherent light before and after the hologram, respectively, the source and image intensity distributions, and the autocorrelation of the hologram can be related in a succinct mathematical relationship. This leads to the development of three computational algorithms based on the autocorrelation function to obtain a quantised hologram with the desired beam-steering capability. These algorithms have their cost functions and performance comparison done at the hologram plane instead of the image plane, which therefore takes less time than traditional image-based methods. Specifically, one of these algorithms is able to save significant time over both the other autocorrelation-based algorithms and the direct binary-search, by 33% and by 50% respectively. A simulation-based study and a corresponding experiment, both reported in this thesis, found that the one of the proposed algorithms had poor power efficiency, whilst the other two were both highly effective in generating digital holograms with precise and power-efficient beam-steering performance. Of these two algorithms, one had superior time performance and was likely the best of the three proposed autocorrelation-based algorithms for generating beam-steering holograms. MIMO-OWC simulation also demonstrated the capability of using beam-steering holograms to design the channel and improve the system performance. Combining reported findings, a strategy can be devised to optimise the throughput of an imaging MIMO-OWC system for a given transmitted power.
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Petersen, Samuel. "Multiple-Input Multiple-Output Systems for Spinning Vehicles." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/605956.
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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, CaliforniaThis paper investigates the performance of a multiple-input multiple-output (MIMO) digital communication system, when the transmitter is located on a spinning vehicle. In particular, a 2x2 MIMO system is used, with Alamouti coding at the transmitter. Both Rayleigh and Rayleigh plus line-of-sight, or Rician, models combined with a deterministic model to simulate the channel. The spinning of the transmitting vehicle, relative to the stationary receive antennas, modulates the signal, and complicates the decoding and channel parameter estimation processes. The simulated system bit error rate is the primary performance metric used. The Alamouti channel code is shown to perform better than the maximal ratio receiver combining (MRRC) and single receiver (2x1) system in some circumstances and performs similarly to the MRRC in the broadside case.
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Zhang, Peichang. "Coherent versus differential multiple-input multiple-output systems." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/376511/.
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In recent years, Multiple-Input-Multiple-Output (MIMO) techniques have attracted substantial attention due to their capability of providing spatial diversity and/or multiplexing gains. Inspired by the concept of Spatial Modulation (SM), the novel concept of Space-Time-Shift-Keying (STSK) was recently proposed, which is considered to have the following advantages: 1) STSK constitutes a generalized shift keying architecture, which is capable of striking the required trade-off between the required spatial and time diversity as well as multiplexing gain and includes SM and Space Shift Keying (SSK) as its special cases. 2) Its high degree of design-freedom, the above-mentioned flexible diversity versus multiplexing gain trade-off can be achieved by optimizing both the number and size of the dispersion matrices, as well as the number of transmit and receive antennas. 3) Similar to the SM/SSK schemes, the Inter-Antenna-Interference (IAI) may be eliminated and consequently, the adoption of single-antenna-based Maximum Likelihood (ML) detection becomes realistic in STSK schemes. In this report, our investigation can be classified into two major categories, Coherent STSK (CSTSK) and Differential STSK (DSTSK) schemes. For CSTSK, since Channel State Information (CSI) is required for data detection, Channel Estimation (CE) techniques become necessary. To be more explicit, we first briefly review the conventional Training Based CE (TBCE) and Semi-Blind CE (SBCE) schemes for the CSTSK MIMO schemes. In addition, we develop a Blockof-Bits Selection Based CE (BBSBCE) algorithm for CSTSK schemes for increasing the overall system’s throughput, while improving the accuracy of the CE. Additionally, it has been widely recognised that MIMO schemes are capable of achieving a diversity and/or multiplexing gain by employing multiple Antenna Elements (AEs) at the transmitter and/or the receiver. However, it should also noted that since MIMO systems utilize multiple RF chains, their power consumption and hardware costs become substantial. Against this background, we introduce the concept of (Antenna Selection) AS and propose a simple yet efficient AS algorithm, namely the Norm-Based Joint Transmit and Receive AS (NBJTRAS) for assisting MIMO systems. For DSTSK, since no CSI is required for differential detection schemes, it also draws our attention. However, in the absence of CE, the Conventional Differential Detection (CDD) schemes usually suffer from a 3 dB performance degradation and may exhibit an error-flow when Doppler frequency is excessive. In order to mitigate this problem, we investigate Multiple-Symbol Differential Sphere Detection (MSDSD) scheme and adopt it in our DSTSK scheme to improve the system performance, while reducing the detection complexity. Furthermore, based on our MSDSD detected DSTSK scheme, we propose a DSTSK aided Multi-User Successive Relaying aided Cooperative System (MUSRC), which is capable of supporting various number of users flexibly, while covering the conventional 50% throughput loss due to the half-duplex transmit and receive constraint of practical transceivers.
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Uppal, Momin Ayub. "Code design for multiple-input multiple-output broadcast channels." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1783.
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Yu, Kai. "Modeling of Multiple-Input Multiple-Output Radio Propagation Channels." Licentiate thesis, KTH, Signals, Sensors and Systems, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1478.
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In recent years, multiple-input multiple-output (MIMO)systems appear to be very promising since they can provide highdata rates in environments with sucient scattering byexploiting the spatial domain. To design a real MIMO wirelesssystem and predict its performance under certain circumstances,it is necessary to have accurate MIMO wireless channel modelsfor dierent scenarios. This thesis presents dierent models forindoor MIMO radio propagation channels based on 5.2 GHz indoorMIMO channel measurements.The recent research on MIMO radio channel modeling isbriey reviewed in this thesis. The models are categorized intonon-physical and physical models. The non-physical modelsprimarily rely on the statistical characteristics of MIMOchannels obtained from the measured data while the physicalmodels describe the MIMO channel (or its distribution) via somephysical parameters. The relationships between dierent modelsare also discussed.For the narrowband case, a non line-of-sight (NLOS)indoor MIMO channel model is presented. The model is based on aKronecker structure of the channel covariance matrix and thefact that the channel is complex Gaussian. It is extended tothe line-of-sight (LOS) scenario by estimating and modeling thedominant component separately.As for the wideband case, two NLOS MIMO channel modelsare proposed. The rst model uses the power delay prole and theKronecker structure of the second order moments of each channeltap to model the wideband MIMO channel while the second modelcombines a simple single-input single-output (SISO) model withthe same Kronecker structure of the second order moments.Monte-Carlo simulations are used to generate indoor MIMOchannel realizations according to the above models. The resultsare compared with the measured data and good agreement has beenobserved.
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Dambul, Katrina D. "Multiple-input multiple-output (MIMO) in optical wireless communications." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558676.
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There is growing demand for indoor wireless communication systems with higher bandwidth and higher data rates. However, the crowded radio frequency (RF) spectrum has caused researchers to consider optical wireless systems. In this thesis, optical signals in the visible region of the spectrum are used. White LEDs are used as transmitters as they provide higher signal-to-noise (SNR) levels and a better link budget than the infrared alternative. Typical modulation bandwidths for white LEDs are limited to tens of MHz. Thus, multiple-input multiple-output (MIMO) transmission is considered as a means to increase data rate. The development of the indoor optical wireless MIMO system begins with the geometrical and mathematical analysis of a single-input single-output (SISO) system and a single-input multiple- output (SIMO) system. The same analysis is then performed for a MIMO system. For the MIMO system, an experimental demonstration using white LEDs and non-imaging receivers are reported. Results include coverage measurements and an SNR analysis. There are limitations using non- imaging receivers, such as coverage limitations and symmetry problems, which cause problem with signal recovery. To improve these limitations, imaging receivers are considered. The design and development of an experimental demonstration of an indoor optical wireless MIMO system with an imaging receiver is presented. The experimental setup consists of a transmitter with a 2 x 2 array of white LEDs and a receiver with a 3 x 3 photo detector array. The system transmits data at a bit rate of 2Mbit/s/channel. Detailed design specifications and optical design are presented. Results show that certain positions within the system coverage area have error-free operation. The BER and SNR analysis shows that the overall BER improves with the overall SNR. In order to exploit the full potential of the system, future work should focus on improving the SNR and BER of the system.
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Gupte, Abhishek. "SOQPSK Signals in Multiple Input Multiple Output (MIMO) Systems." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/605954.
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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, CaliforniaThis paper investigates the use of shaped offset quadrature phase shift keying (SOQPSK) signals in multiple-input multiple-output (MIMO) communication systems. The goal is to integrate commonly used receiver architectures for conventional single-input single-output (SISO) systems into a corresponding MIMO system. The benefits of improved spectral efficiency are juxtaposed against the increased receiver complexity. Bit error rate performances for the SISO and MIMO architectures in a multipath environment are compared and conclusions regarding trade-offs between signal to noise ratio (SNR) and spectral efficiency stated.
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Stewart, Kyle Bradley. "Waveform-Diverse Multiple-Input Multiple-Output Radar Imaging Measurements." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1450437383.
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Najam, Ali Imran. "Multiple-input multiple-output antennas for ultra wideband communications." Grenoble INPG, 2010. http://www.theses.fr/2010INPG0043.
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La radio Ultra Large Bande (ULB) promet de nouveaux marchés dans les domaines des réseaux personnels hauts débits et de capteurs. De sorte à améliorer la robustesse du lien radio et le débit, l’association des techniques MIMO à l’ULB a été envisagée. En vue d’une réalisation pratique, un challenge fondamental reste la conception des antennes qui doivent répondre aux contraintes de l’ULB et des systèmes multi-antennaires, et aux contraintes physiques et économiques. Dans ce contexte, plusieurs nouveaux designs d’antennes MIMO ULB sont proposés. Leur caractérisation s’appuie sur les paramètres conventionnels utilisés en conception d’antennes ainsi que des paramètres spécifiques à l’ULB et au MIMO. En particulier, un nouveau design compact présentant une forte isolation grâce à l’insertion d’un stub sur le plan de masse est proposé. Une nouvelle méthode de modélisation du couplage mutuel, qui présente l’avantage d’offrir de nouvelles approches pour le compenser, est également introduiteUWB technology has rapidly emerged in the areas of WPAN and sensors networks featuring high data rate communications. The applications of UWB are limited to very short-range communications due to the extremely low transmitted power. The combination of MIMO techniques with UWB has been considered as a solution to improve the range. However, a fundamental challenge arises for the design of antennas that faces the constraints offered by UWB systems and multi-antennas systems, and the constraints of size and cost. In this context, several new UWB-MIMO antennas are proposed. Their characterization is based on the parameters relevant to conventional antenna design and the specific parameters relevant to the UWB-MIMO antenna design. In particular, a new compact design with high isolation by inserting the inverted-Y shaped stub on the ground plane is proposed. A new method for modelling the mutual coupling, is also introduced which has the advantage of offering new approach to compensate it
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Di, Viesti Pasquale <1994>. "Colocated multiple-input multiple-output radars for smart mobility." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10113/1/Di_Viesti_Pasquale_Thesis.pdf.
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In recent years, radars have been used in many applications such as precision agriculture and advanced driver assistant systems. Optimal techniques for the estimation of the number of targets and of their coordinates require solving multidimensional optimization problems entailing huge computational efforts. This has motivated the development of sub-optimal estimation techniques able to achieve good accuracy at a manageable computational cost. Another technical issue in advanced driver assistant systems is the tracking of multiple targets. Even if various filtering techniques have been developed, new efficient and robust algorithms for target tracking can be devised exploiting a probabilistic approach, based on the use of the factor graph and the sum-product algorithm.
The two contributions provided by this dissertation are the investigation of the filtering and smoothing problems from a factor graph perspective and the development of efficient algorithms for two and three-dimensional radar imaging. Concerning the first contribution, a new factor graph for filtering is derived and the sum-product rule is applied to this graphical model; this allows to interpret known algorithms and to develop new filtering techniques. Then, a general method, based on graphical modelling, is proposed to derive filtering algorithms that involve a network of interconnected Bayesian filters. Finally, the proposed graphical approach is exploited to devise a new smoothing algorithm. Numerical results for dynamic systems evidence that our algorithms can achieve a better complexity-accuracy tradeoff and tracking capability than other techniques in the literature. Regarding radar imaging, various algorithms are developed for frequency modulated continuous wave radars; these algorithms rely on novel and efficient methods for the detection and estimation of multiple superimposed tones in noise. The accuracy achieved in the presence of multiple closely spaced targets is assessed on the basis of both synthetically generated data and of the measurements acquired through two commercial multiple-input multiple-output radars.
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Fricker, Thomas. "Emulators for multiple output computer models." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522445.
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Graham, Martin. "Visualising multiple overlapping classification hierarchies." Thesis, Edinburgh Napier University, 2001. http://researchrepository.napier.ac.uk/Output/2430.
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The revision or reorganisation of hierarchical data sets can result in many possible hierarchical classifications composed of the same or overlapping data sets existing in parallel with each other. These data sets are difficult for people to handle and conceptualise, as they try to reconcile the different perspectives and structures that such data represents. One area where this situation occurs is the study of botanical taxonomy, essentially the classification and naming of plants. Revisions, new discoveries and new dimensions for classifying plants lead to a proliferation of classifications over the same set of plant data. Taxonomists would like a method of exploring these multiple overlapping hierarchies for interesting information, correlations, or anomalies. The application and extension of Information Visualisation (IV) techniques, the graphical display of abstract information, is put forward as a solution to this problem. Displaying the multiple classification hierarchies in a visually appealing manner along with powerful interaction mechanisms for examination and exploration of the data allows taxonomists to unearth previously hidden information. This visualisation gives detail that previous visualisations and statistical overviews cannot offer. This thesis work has extended previous IV work in several respects to achieve this goal. Compact, yet full and unambiguous, hierarchy visualisations have been developed. Linking and brushing techniques have been extended to work on a higher class of structure, namely overlapping trees and hierarchies. Focus and context techniques have been pushed to achieve new effects across the visually distinct representations of these multiple hierarchies. Other data types, such as multidimensional data and large cluster hierarchies have also been displayed using the final version of the visualisation.
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Yu, Kai. "Multiple-Input Multiple-Output Radio Propagation Channels : Characteristics and Models." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-138.
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Bale, Viktor. "Computationally efficient equalisation of broadband multiple-input multiple-output systems." Thesis, University of Southampton, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437110.
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Li, Ran. "Optical multiple input and multiple output (MIMO) in multimode fibre." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:1770da43-e93b-462b-866f-beb5f972ce06.
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Recently, there has been a dramatic increase in the amount of data transmission within short range local area networks (LAN). Multimode fibre (MMF) is widely used in local area networks because of its coupling and alignment along with the low cost of related components. Graded index MMF has become common due to the reduction in pulse spreading; however, as demands for high bandwidth increase towards a future gigabit rate network, the typical MMF using conventional transmission methods will not be suitable. Meanwhile, this increasing demand for high speed data transmission will soon reach the Shannon capacity limit of single mode fibres. After multiple input and multiple output (MIMO) technology was successfully used in wireless communication, the researcher realised that the same idea could also be applied to an optical fibre network. Optical MIMO techniques are gaining interest in order to create parallel channels over orthogonal modes in a MMF or a few mode fibre (FMF). This approach could lead to a significant increase in the bandwidth distance product and be employed in the next 40Gb/s or even 100Gb/s optical fibre transmission systems. Generally speaking, optical MIMO appears to be the best solution to the bandwidth limitation problem in either short distance MMF or long distance FMF systems. This thesis focuses on designing a simple, cost-effective, and energy efficient optical MIMO system based on MMFs. This proposed system can be realised by combining radial offset launching and annular multi-segment detectors. First, in the initial work, we performed a theoretical and numerical study of the key impairments of MMFs, and the mode propagation in an MMF was analysed mathematically. The variation in electrical field intensity for linearly polarised (LP) modes in the core region of an MMF and the analytical solutions for power coupling coefficients in either radial offset launching or centre launching were presented. In addition, the modal time delays, impulse response, and transfer function were all introduced. Subsequently, the near field intensity pattern (NFP) was simulated at the output facet of the MMF, which indicated that the overall NFP suffered from blurring when it contained mode mixing, and that the intensity pattern was particularly sensitive to the random phase. According to the spatial distribution of the NFP, the annular detector can be exploited more efficiently. All of the results were calculated and plotted using the MATLAB program. Secondly, the optical MIMO model in the multimode fibre was briefly summarised, including the MIMO channel matrix H expression, a mathematical expression of optical MIMO capacity, MIMO channel estimation and an equalization method. Two metrics can be used to characterise the MIMO channel performance: condition number and crosstalk at each receiver. The numerical results demonstrated that the new type of annular multi-segment detector exhibits superior performance compared to the conventional multiple single mode fibre (SMF) detectors, making them attractive for future optical MIMO systems. Finally, the core work of this thesis can be divided into two parts: the modelling of a 10Gb/s intensity modulation direct detection (IM-DD) optical MIMO MMF system; and the modelling of an advanced 10Gb/s coherent differential phase shift keying (DPSK) MIMO FMF system. In both simulation systems, the important transmission parameters of intra-group mode mixing, modal dispersion, chromatic dispersion, and mode attenuation were considered and discussed in detail. In the IM-DD optical MIMO system, the optimization of the transceiver can be based upon the laser spot size and the power flux distribution emitted by the transmitter. Results from the simulation showed that the intra-group mode mixing had a limited impact on system performance, and due to its inability to compensate for linear impairments, the IM-DD optical MIMO was not favourable for long distance transmission systems. Nevertheless, the new type of optical fibre FMF seems to be the most promising candidate for use in long haul transmission systems. Therefore, the well-known DPSK modulation format in conjugation with the coherent detection deployed in FMF was studied. Both heterodyne and intradyne detection schemes were analysed followed by mathematical derivation and numerical simulation; the results illustrated that similar system performances can be achieved in both schemes. Meanwhile, the coherent DPSK simulation results also demonstrated that the linear impairments were almost compensated by the frequency domain MIMO equalization process, which resulted in system performance being independent to transmission distance for up to 10km. This advantage proved that the coherent optical DPSK MIMO system can be employed in long haul networks. As with an IM-DD optical MIMO system, optimization of a coherent MIMO system was also possible. However, in contrast to the optimization of an IM-DD MIMO system, a trade-off had to be made between sufficient spatial diversity at the transceiver and differential modal delay caused by modal dispersion; consequently, the numerical results showed that the proposed coherent optical DPSK MIMO gained reasonable good results without using any active device, such as a spatial light modulator and a mode converter. In conclusion, this proposed optical MIMO system provided easy implementation and integration and is feasible for use in future optical communication systems.
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Cao, Pan. "Resource Allocation for Multiple-Input and Multiple-Output Interference Networks." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-161382.
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To meet the exponentially increasing traffic data driven by the rapidly growing mobile subscriptions, both industry and academia are exploring the potential of a new genera- tion (5G) of wireless technologies. An important 5G goal is to achieve high data rate. Small cells with spectrum sharing and multiple-input multiple-output (MIMO) techniques are one of the most promising 5G technologies, since it enables to increase the aggregate data rate by improving the spectral efficiency, nodes density and transmission bandwidth, respectively. However, the increased interference in the densified networks will in return limit the achievable rate performance if not properly managed.
The considered setup can be modeled as MIMO interference networks, which can be classified into the K-user MIMO interference channel (IC) and the K-cell MIMO interfering broadcast channel/multiple access channel (MIMO-IBC/IMAC) according to the number of mobile stations (MSs) simultaneously served by each base station (BS). The thesis considers two physical layer (PHY) resource allocation problems that deal with the interference for both models: 1) Pareto boundary computation for the achiev- able rate region in a K-user single-stream MIMO IC and 2) grouping-based interference alignment (GIA) with optimized IA-Cell assignment in a MIMO-IMAC under limited feedback. In each problem, the thesis seeks to provide a deeper understanding of the system and novel mathematical results, along with supporting numerical examples. Some of the main contributions can be summarized as follows.
It is an open problem to compute the Pareto boundary of the achievable rate region for a K-user single-stream MIMO IC. The K-user single-stream MIMO IC models multiple transmitter-receiver pairs which operate over the same spectrum simultaneously. Each transmitter and each receiver is equipped with multiple antennas, and a single desired data stream is communicated in each transmitter-receiver link. The individual achievable rates of the K users form a K-dimensional achievable rate region. To find efficient operating points in the achievable rate region, the Pareto boundary computation problem, which can be formulated as a multi-objective optimization problem, needs to be solved. The thesis transforms the multi-objective optimization problem to two single-objective optimization problems–single constraint rate maximization problem and alternating rate profile optimization problem, based on the formulations of the ε-constraint optimization and the weighted Chebyshev optimization, respectively. The thesis proposes two alternating optimization algorithms to solve both single-objective optimization problems. The convergence of both algorithms is guaranteed. Also, a heuristic initialization scheme is provided for each algorithm to achieve a high-quality solution. By varying the weights in each single-objective optimization problem, numerical results show that both algorithms provide an inner bound very close to the Pareto boundary. Furthermore, the thesis also computes some key points exactly on the Pareto boundary in closed-form.
A framework for interference alignment (IA) under limited feedback is proposed for a MIMO-IMAC. The MIMO-IMAC well matches the uplink scenario in cellular system, where multiple cells share their spectrum and operate simultaneously. In each cell, a BS receives the desired signals from multiple MSs within its own cell and each BS and each MS is equipped with multi-antenna. By allowing the inter-cell coordination, the thesis develops a distributed IA framework under limited feedback from three aspects: the GIA, the IA-Cell assignment and dynamic feedback bit allocation (DBA), respec- tively. Firstly, the thesis provides a complete study along with some new improvements of the GIA, which enables to compute the exact IA precoders in closed-form, based on local channel state information at the receiver (CSIR). Secondly, the concept of IA-Cell assignment is introduced and its effect on the achievable rate and degrees of freedom (DoF) performance is analyzed. Two distributed matching approaches and one centralized assignment approach are proposed to find a good IA-Cell assignment in three scenrios with different backhaul overhead. Thirdly, under limited feedback, the thesis derives an upper bound of the residual interference to noise ratio (RINR), formulates and solves a corresponding DBA problem. Finally, numerical results show that the proposed GIA with optimized IA-Cell assignment and the DBA greatly outperforms the traditional GIA algorithm.
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Waters, Deric Wayne. "Signal Detection Strategies and Algorithms for Multiple-Input Multiple-Output Channels." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7514.
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In todays society, a growing number of users are demanding more sophisticated services from wireless communication devices. In order to meet these rising demands, it has been proposed to increase the capacity of the wireless channel by using more than one antenna at the transmitter and receiver, thereby creating multiple-input multiple-output (MIMO) channels. Using MIMO communication techniques is a promising way to improve wireless communication technology because in a rich-scattering environment the capacity increases linearly with the number of antennas. However, increasing the number of transmit antennas also increases the complexity of detection at an exponential rate. So while MIMO channels have the potential to greatly increase the capacity of wireless communication systems, they also force a greater computational burden on the receiver.
Even suboptimal MIMO detectors that have relatively low complexity, have been shown to achieve unprecedented high spectral efficiency. However, their performance is far inferior to the optimal MIMO detector, meaning they require more transmit power. The fact that the optimal MIMO detector is an impractical solution due to its prohibitive complexity, leaves a performance gap between detectors that require reasonable complexity and the optimal detector. The objective of this research is to bridge this gap and provide new solutions for managing the inherent performance-complexity trade-off in MIMO detection.
The optimally-ordered decision-feedback (BODF) detector is a standard low-complexity detector. The contributions of this thesis can be regarded as ways to either improve its performance or reduce its complexity - or both.
We propose a novel algorithm to implement the BODF detector based on noise-prediction. This algorithm is more computationally efficient than previously reported implementations of the BODF detector. Another benefit of this algorithm is that it can be used to easily upgrade an existing linear detector into a BODF detector.
We propose the partial decision-feedback detector as a strategy to achieve nearly the same performance as the BODF detector, while requiring nearly the same complexity as the linear detector.
We propose the family of Chase detectors that allow the receiver to trade performance for reduced complexity. By adapting some simple parameters, a Chase detector may achieve near-ML performance or have near-minimal complexity. We also propose two new detection strategies that belong to the family of Chase detectors called the B-Chase and S-Chase detectors. Both of these detectors can achieve near-optimal performance with less complexity than existing detectors.
Finally, we propose the double-sorted lattice-reduction algorithm that achieves near-optimal performance with near-BODF complexity when combined with the decision-feedback detector.
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Ding, Minhua. "Multiple-input multiple-output wireless system designs with imperfect channel knowledge." Thesis, Kingston, Ont. : [s.n.], 2008. http://hdl.handle.net/1974/1335.
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Eitel, Emna [Verfasser]. "Tracking of Time-Varying Multiple Input Multiple Output Channels / Emna Eitel." München : Verlag Dr. Hut, 2014. http://d-nb.info/1047994879/34.
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Dai, Xiaoguang, and 戴晓光. "Receiver complexity reduction of multiple-input multiple-output wireless communication systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46589508.
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McNamara, Darren Phillip. "Characterisation and investigation of multiple-input multiple-output wireless communication channels." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274672.
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Rzepniewski, Adam K. (Adam Kamil) 1976. "Cycle-to-cycle control of multiple input-multiple output manufacturing processes." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32392.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005."June 2005."
Includes bibliographical references (leaves 199-200).
In-process closed-loop control of many manufacturing processes is impractical owing to the impossibility or the prohibitively high cost of placing sensors and actuators necessary for in-process control. Such processes are usually left to statistical process control methods, which only identify problems without specifying solutions. In this thesis, we look at a particular kind of manufacturing process control, cycle-to-cycle control. This type of control is similar to the better known run-by-run control. However, it is developed from a different point of view allowing easy analysis of the process' transient closed-loop behavior due to changes in the target value or to output disturbances. Both types are methods for using feedback to improve product quality for processes that are inaccessible within a single processing cycle but can be changed between cycles. Through rigorous redevelopment of the control equations, we show these methods are identical in their response to output disturbances, but different in their response to changes in the target specification. Next, we extend these SISO results to multiple input-multiple output processes. Gain selection, stability, and process variance amplification results are developed. Then, the limitation of imperfect knowledge of the plant model is imposed. This is consistent with manufacturing environments that require minimal cost and number of tests in determining a valid process model. The effects of this limitation on system performance and stability are discussed. To minimize the number of pre-production experiments, a generic, easily calibrated model is developed for processes with a regional-type coupling between the inputs and outputs, in which one input affects a region of outputs.
(cont.) This model can be calibrated in just two experiments and is shown to be a good predictor of the output. However, it is determined that models for this class of process are ill- conditioned for even moderate numbers of inputs and outputs. Therefore, controller design methods that do not rely on direct plant gain inversion are sought and a representative set is selected: LQR, LQG, and H-infinity. Robust stability bounds are computed for each design and all results are experimentally verified on a 110 input- 10 output discrete-die sheet metal forming process, showing good agreement.
by Adam Kamil Rzepniewski.
Ph.D.
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Bahceci, Israfil. "Multiple-Input Multiple-Output Wireless Systems: Coding, Distributed Detection and Antenna Selection." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08262005-022321/.
Full textAbstract:
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006.Altunbasak, Yucel, Committee Chair ; Mersereau, Russell M., Committee Member ; Fekri, Faramarz, Committee Member ; Smith, Glenn, Committee Member ; Huo, Xiaoming, Committee Member. Includes bibliographical references.
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Yue, Guosen. "Code optimization and analysis for multiple-input and multiple-output communication systems." Diss., Texas A&M University, 2004. http://hdl.handle.net/1969.1/2758.
Full textAbstract:
Design and analysis of random-like codes for various multiple-input and multiple-output communication systems are addressed in this work. Random-like codes have drawn significant interest because they offer capacity-achieving performance. We first consider the analysis and design of low-density parity-check (LDPC) codes for turbo multiuser detection in multipath CDMA channels. We develop techniques for computing the probability density function (pdf) of the extrinsic messages at the output of the soft-input soft-output (SISO) multiuser detectors as a function of the pdf of input extrinsic messages, user spreading codes, channel impulse responses, and signal-to-noise ratios. Using these techniques, we are able to accurately compute the thresholds for LDPC codes and design good irregular LDPC codes. We then apply the tools of density evolution with mixture Gaussian approximations to optimize irregular LDPC codes and to compute minimum operational signal-to-noise ratios for ergodic MIMO OFDM channels. In particular, the optimization is done for various MIMO OFDM system configurations which include different number of antennas, different channel models and different demodulation schemes. We also study the coding-spreading tradeoff in LDPC coded CDMA systems employing multiuser joint decoding. We solve the coding-spreading optimization based on the extrinsic information SNR evolution curves for the SISO multiuser detectors and the SISO LDPC decoders. Both single-cell and multi-cell scenarios will be considered. For each of these cases, we will characterize the extrinsic information for both finite-size systems and the so-called large systems where asymptotic performance results must be evoked. Finally, we consider the design optimization of irregular repeat accumulate (IRA) codes for MIMO communication systems employing iterative receivers. We present the density evolution-based procedure with Gaussian approximation for optimizing the IRA code ensemble. We adopt an approximation method based on linear programming to design an IRA code with the extrinsic information transfer (EXIT) chart matched to that of the soft MIMO demodulator.
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Milliner, David Louis. "Low-complexity list detection algorithms for the multiple-input multiple-output channel." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/37248.
Full textAbstract:
Modern communication systems demand ever-increasing data rates. Meeting this increased demand is not easy due to regulation and fundamental physical constraints. The utilization of more than one antenna at both the transmitter and receiver produces a multiple-input multiple-output (MIMO) channel, thereby enabling (under certain channel conditions) increased data rates without the need for increased bandwidth or transmission power. Concurrent with this increase in bandwidth is an increase in the receiver's computational complexity which, for a brute-force detector, increases exponentially. For receivers that possess error correcting capabilities, the problem of constructing a detector with low computational complexity that allows for near-exact a posteriori detection is challenging for transmission schemes employing even a modest number of transmit antennas and modulation alphabet sizes. The focus of this dissertation is on the construction of MIMO detection algorithms with low and fixed computational complexity. Specifically, the detection algorithms in this dissertation generate a list of potential transmission vectors resulting in realizable communication receivers with low and fixed computational complexity combined with low error rate performance in both coded and uncoded systems.
A key contribution in this dissertation is a breadth-first fixed-complexity algorithm known as the smart-ordered and candidate-adding algorithm that achieves a desirable performance-complexity tradeoff. This algorithm requires only a single pass of a search tree to find its list of transmission vectors. We then construct a framework within which we classify a large class of breadth-first detection algorithms.
The design of receiver algorithms for MIMO systems employing space-time codes and error correction is an important area of study. In this dissertation we propose a low and fixed computational complexity algorithm for an increasingly significant algebraic space-time code known as the golden code.
The notion of computational complexity is critical in the design of practical MIMO receivers. We provide an analysis of computational complexity in relation to list-based soft-output detection where, in some instances, bounds are placed on the computational complexity of MIMO detection. For this analysis we utilize a metric known as the number of branch metric computations.
The value at which the log-likelihood ratio (LLR) of conditional probabilities for a transmitted bit being either a 1 or a 0 is 'clipped' has an impact on a system's error rate performance. We propose a new approach for determining LLR clipping levels that, in contrast to prior approaches which clip to a predetermined fixed LLR clipping level, exploits channel state information to improve the error rate performance of suboptimal detection algorithms.
Orthogonal frequency-division (OFDM) multiplexing is an effective technique for combating frequency-selective wideband communication channels. It is common practice for MIMO-OFDM detectors to implement the same detector at each subcarrier, in which case the overall performance is dominated by the weakest subcarrier. We propose a hard-output list detection receiver strategy for MIMO-OFDM channels called nonuniform computational complexity allocation, whereby the receiver adapts the computational resources of the MIMO detector at each subcarrier to match a metric of the corresponding channel quality. The proposed nonuniform algorithm improves performance over uniform allocation.
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Khalid, Farhan [Verfasser]. "Hybrid Precoding for Multiuser Multiple-Input Multiple-Output Mobile Communications / Farhan Khalid." Aachen : Shaker, 2013. http://d-nb.info/1051575907/34.
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Gulati, Vivek. "Concatenated codes for the multiple-input multiple-output quasi-static fading channel." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1477.
Full textAbstract:
The use of multiple antennas at the transmitter and/or the receiver promises
greatly increased capacity. This can be useful to meet the ever growing demand
of wireless connectivity, provided we can find techniques to efficiently exploit the
advantages of the Multiple-Input Multiple-Output (MIMO) system.
This work explores the MIMO system in a flat quasi-static fading scenario. Such
a channel occurs, for example, in packet data systems, where the channel fade is constant
for the duration of a codeword and changes independently from one transmission
to another. We first show why it is hard to compute the true constrained modulation
outage capacity. As an alternative, we present achievable lower bounds to this capacity
based on existing space-time codes. The bounds we compute are the fundamental
limits to the performance of these space-time codes under maximum-likelihood decoding,
optimal outer codes and asymptotically long lengths. These bounds also indicate
that MIMO systems have different behavior under Gaussian signaling (unconstrained
input) and under the finite alphabet setting. Our results naturally suggest the use of
concatenated codes to approach near-capacity performance. However, we show that a
system utilizing an iterative decoder has a fundamental limit it cannot be universal
and therefore it cannot perform arbitrarily close to its outage limit.
Next, we propose two different transceiver structures that have good performance.
The first structure is based on a novel BCJR-decision feedback decoder which
results in performance within a dB of the outage limit. The second structure is based
on recursive realizations of space-time trellis codes and uses iterative decoding at the
receiver. This recursive structure has impressive performance even when the channel
has time diversity. Thus, it forms the basis of a very flexible and robust MIMO
transceiver structure.
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Schneider, Daniel [Verfasser]. "Inhome Power Line Communications using Multiple Input Multiple Output Principles / Daniel Schneider." München : Verlag Dr. Hut, 2012. http://d-nb.info/1022535307/34.
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Webb, Matthew William. "Analysis of multiple-input multiple-output wireless communication systems in cochannel interference." Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435743.
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Lee, Zhi Hou. "Improved multiple input multiple output blind equalization algorithms for medical implant communication." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28726/.
Full textAbstract:
Medical implant sensor that is used to monitor the human physiology signals is helpful to improve the quality of life and prevent severe result from the chronic diseases. In order to achieve this, the wireless implant communication link that delivers the monitored signal to a multiple antennas external device is an essential portion. However, the existing conventional narrow band Medical Implant Communications System (MICS) has low data rate because of the bandlimited channel is allocated. To improve the data rate in the radio frequency communication, ultra-wide band technology has been proposed. However, the ultra-wide band technology is relatively new and requires living human to be the test subject in order to validate the technology performance. In this condition, the test on the new technology can rise ethical challenge. As a solution, we improve the data rate in the conventional narrow band MICS. The improvement of data rate on the narrow band implies the information bandwidth is larger than the allocated channel bandwidth, and therefore the high frequency components of the information can loss. In this case, the signal suffers the intersymbol-interference (ISI). Instead of that, the multiple antennas external device can receive the signal from other transmitting implant sensor which has the same operating frequency. As a result, the signal is further hampered by co-channel interference (CCI). To recover the signal from the ISI and CCI, multiple-input multiple output (MIMO) blind equalization that has source separation ability can be exploited. Cross-Correlation Constant Modulus Algorithm (CC-CMA) is the conventional MIMO blind equalization algorithm that can suppress ISI and CCI and able to perform source separation. However, CC-CMA has only been analyzed and simulated in the modulation of Phase Shift Keying (PSK). The performance of CC-CMA in multi-modulus modulation scheme such as 4-Pulse-amplitude modulation (PAM) and 16-Quadrature amplitude modulation (QAM), which has higher data rate than PSK, has not been analyzed. Therefore, our work is to analysis and optimize CC-CMA on the multi-modulus modulation scheme. From our analysis, we found that the cost function of CC-CMA is biased cost function. Instead of that, from our simulation, CC-CMA introduces an unexpected shrinking effect whereby the amplitudes of the equalizer outputs have been reduced, especially in multi-modulus modulation scheme. This shrinking effect is not severe in PSK because the decision of a PSK symbol is based on phase, but not amplitude. Unfortunately, this is severe in multi-modulus modulation scheme. To overcome this shrinking effect in multi-modulus modulation scheme, we propose Cross-Independent Constant Modulus Algorithm (CI-CMA). Based on the convergence analysis, we identify the new optimum dispersion value and mixing parameter in CI-CMA. From the simulation results, we confirm that CI-CMA is able to perform equalization and source separation in the multi-modulus modulation scheme. In order to improve the steady state performance of CI-CMA, we perform the steady state mean square error (MSE) analysis of CI-CMA using the energy preservation theorem that was developed by Mai and Sayed in 2001, and our result is more accurate than the previous work. From our analysis, only the reduction in adaptation step size can reduce the steady state MSE, but it is well known that the MSE is indeed a tradeoff with the speed of convergence. Therefore without sacrificing convergence speed, our last effort is to propose hybrid algorithms. The hybrid algorithms are done by combining a new adaptive constant modulus algorithm (ACMA), a decision directed algorithm and a cross-correlation function. From the simulation results, we found that the hybrid algorithms can show low steady state error and thereby improve the reliability of the communication link. The main achievement of this thesis is the discovery of new dispersion value through the convergence analysis.
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Spencer, Quentin H. "Transmission Strategies for Wireless Multi-user, Multiple-Input, Multiple-Output Communication Channels." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd378.pdf.
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Shanmugam, Pravinkumar. "Multiple-user multiple-input multiple-output beam-forming and frequency reuse in millimeter wave communication." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1603753.
Full textAbstract:
This paper explains a new beam-forming technique implemented in a deterministic Multiple-Input Multiple-Output (MIMO) channel model in 60 GHz millimeter wave frequency. We calculate path loss between the transmitter and receiver antenna elements in the line of sight path. Assuming that Channel State Information (CSI) is known as the deterministic values at the transmitter, the Composite Transfer Function (CTF) derived from the CSI generates orthogonal beams. The orthogonal beam allows us to reuse the frequency at the same time slot with the capability of multi-user MIMO. Our beam forming technique controls the radiated power at the transmitter in such a way that the power received at a particular receiving antenna element is 0dB, and it is suppressed to less than -60dB at other receiving elements. We study the performance of our proposed beam-forming technique by transmitting the QPSK modulated signal through the orthogonal beams, and analyzing the bit error rate curve.
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Li, Yikai. "Non-Orthogonal Multiple Access for Massive Multiple-Input Multiple-Output Relay-Aided/Cell-Free Networks." OpenSIUC, 2021. https://opensiuc.lib.siu.edu/dissertations/1906.
Full textAbstract:
The recent developments in Internet-of-Things (IoT) and the next-generation wireless communication systems (5G and beyond) are posing unprecedented demands for massive connectivity, enhanced spectrum efficiency, and strengthened reliability. Moreover, the conventional orthogonal multiple access (OMA) techniques have approached their fundamental limits or the improvements in performance are marginal. To this end, a paradigm-shift from OMA to massive multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) technology is proposed. The proposed techniques are capable of serving multiple spatially-distributed user nodes/IoTs in the same frequency-time resource block by reaping out the benefits of power-domain NOMA, and favorable propagation and channel hardening brought by very large antenna arrays.First, a comprehensively literature survey has been conducted. Next, system, channel and signal models were developed by considering practical transmission impairments of the proposed massive MIMO NOMA. Then, novel NOMA relaying strategies via massive MIMO with pilot designs, per-hop and cascaded channel estimation, statistical-parameter based power allocation policy, and reliable precoding scheme are designed. Then, a complete analytical framework to derive the fundamental performance metrics is developed. A MATLAB-based simulation framework is developed to verify the proposed system designs.Then, the detrimental effects of residual interference caused by intra-cluster pilot sharing and error propagation caused by imperfect successive interference cancellation are quantified. The results acquired can provide insights for refining the proposed techniques in terms of signal model and pilot design.Trade-offs among massive connectivity and spectral efficiency will be established and refined for the proposed relay aided/cell-free massive MIMO NOMA via carefully designing per-hop and cascaded channel estimation, low-complexity statistical-parameter-based power allocation, and conjugate precoding schemes. The proposed technique is expected to significantly outperform the conventional OMA scheme in all overloaded system scenarios by virtue of the proposed aggressive spatial multiplexing and power-domain NOMA techniques. Hence, the proposed technique can simultaneously serve many users with fast data rates than that of the existing OMA techniques. The proposed NOMA techniques are expected to provide higher spectral and energy efficiencies with ultra-low end-to-end latency than those of existing OMA. Thus, the proposed relay-aided/cell-free massive MIMO NOMA can significantly contribute as a novel candidate technology for the next-generation wireless standards.
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Wong, Kevin. "Multiple Input Single Output (MISO) Tablet/ Phone Charger." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/925.
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This thesis entails the design and implementation of a multiple input single output (MISO) DC-DC converter using the flyback topology to charge tablets/ smartphones or any USB powered portable device. The MISO converter will enable the use of various renewable energy sources such as a solar panel/ rechargeable battery combination, bicycle dynamo, hydroelectric power, and wind turbine. This paper will cover the design, simulations, and test results of the MISO converter. The flyback topology was chosen due to its low part count and its efficiency at low power. The proposed converter has a nominal 12V input to output USB 2.0 requirements (5V at 2.5W). Results from both computer simulation using LTSpice and hardware tests demonstrate the functionality of the proposed MISO converter with solar/battery and bicycle dynamo inputs. Overall performance of the converter in terms of efficiency, line and load regulations, as well as its charging ability to a cell phone will be presented in this report.
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Igoniderigha, Nseabasi Ekaette. "Data navigation and visualization : navigating coordinated multiple views of data." Thesis, Edinburgh Napier University, 2015. http://researchrepository.napier.ac.uk/Output/8832.
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The field of coordinated and multiple views (CMVs) has been for over a decade, a promising technique for enhancing data visualization, yet that promise remains unfulfilled. Current CMVs lack a platform for flexible execution of certain kinds of open-ended tasks consequently users' are unable to achieve novel objectives. Navigation of data, though an important aspect of interactive visualization, has not generated the level of attention it should from the human computer interaction community. A number of frameworks for and categorization of navigation techniques exist, but further detailed studies are required to highlight the range of benefits improved navigation can achieve in the use of interactive tools such as CMVs. This thesis investigates the extent of support offered by CMVs to people navigating information spaces, in order to discover data, visualize these data and retrieve adequate information to achieve their goals. It also seeks to understand the basic principle of CMVs and how to apply its procedure to achieve successful navigation. Three empirical studies structured around the user's goal as they navigate CMVs are presented here. The objective of the studies is to propose a simple, but strong, design procedure to support future development of CMVs. The approach involved a comparative analysis of qualitative and quantitative experiments comprising of categorised navigation tasks carried out, initially on existing CMVs and subsequently on CMVs which had been redesigned applying the proposed design procedure. The findings show that adequate information can be retrieved, with successful navigation and effective visualization achieved more easily and in less time, where metadata is provided alongside the relevant data within the CMVs to facilitate navigation. This dissertation thus proposes and evaluates a novel design procedure to aid development of more navigable CMVs.
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Tong, Yajian. "Multiple-input multiple-output converters for future low-voltage DC power distribution architectures." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52780.
Full textAbstract:
Multiple-input multiple-output (MIMO) converters have been identified as a cost-effective approach for energy harvesting and dispatching in hybrid power systems such as those envisioned in future smart homes and DC microgrids. Compared with relatively complex set-up of single-input single-output (SISO) converters linked at a common DC bus to exchange power, the MIMO converters possess promising features of fewer components, higher power density, and centralized control. This thesis addresses various issues regarding the development of MIMO converters. Both non-isolated and isolated MIMO converter topologies are proposed. Steady-state analysis and dynamic modeling of MIMO non-inverting buck–boost and flyback converters are introduced and presented in detail. Specific switching strategies are proposed and appropriate control algorithms are presented to enable power budgeting between diverse sources and loads in addition to regulating output voltages. Furthermore, a simple method is put forward for deriving the non-isolated MIMO converters with DC-link inductor (DLI) and DC-link capacitor (DLC). Based on a basic structure, a set of rules is listed for the synthesis of MIMO converters. Using the time-sharing concept, multiple sources provide energy in one period, and multiple loads draw energy in the subsequent period. In the end, general techniques are introduced for extending the SISO converters to their MIMO versions, where parts of the conventional SISO converters are replaced with multiport structures. It is envisioned that MIMO converters presented in this thesis will find their acceptance in the future in various applications with DC distribution, which are becoming increasingly accepted by industry.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Zhang, Yuqi. "Lattice Reduction Aided Multiple Input Multiple Output Detection Algorithm Design For 5G Communication." Thesis, KTH, Teknisk informationsvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209559.
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In recent years, multiple input multiple output system has raised intensive researchinterests for its huge potentials to achieve higher spectral efficiency anddata rate. However, transmitting multiple data streams through the same timeand frequency resources simultaneously leads to severe interference betweentransmitted signals. In order to solve this problem, lattice reduction is proposedas a suboptimal maximum likelihood algorithm. It aims at finding aset of better basis vectors for the channel matrix and results in satisfactoryperformance improvements compared to conventional linear detectors. But theaverage complexity of lattice reduction algorithm is too high for practical uses.This thesis studies conventional linear detection algorithms and lattice reductionaided detection algorithms for uplink receiver design. Further an iterativelattice reduction algorithm is proposed by exploiting the frequency coherence inan orthogonal frequency division multiplexing system to achieve low complexity.In this thesis, algorithm performances are verified in various scenarios throughsimulations. Results show promising performance improvements for presentedlattice reduction detection algorithms, at the cost of an acceptable complexityincrease.Under de senaste åren har MIMO system fått ökat intensiva forskningsintressenför sina stora möjligheter att uppnå högre spektral effektivitet och datahastighet.Överföring av era dataströmmar i samma tid och frekvensresurser lederemellertid samtidigt till allvarlig störning mellan sända signaler. För att lösadetta problem föreslås lattice reduction som en suboptimal maximal likelihoodalgorithm. Det syftar till att hitta en uppsättning bättre basviktorer för kanalmatrisenoch resultera i tillfredsställande prestandaförbättringar jämfört medkonventionella linjära detektorer. Men den genomsnittliga komplexiteten hoslattice reduction är för hög för praktiska användningsområden. Denna avhandlingstuderar konventionella linjära detekteringsalgoritmer och lattice reductiondetekteringsalgoritmer för uplink-mottagare. Vidare föreslås en iterativ latticereduction algoritm genom utnyttjande av frekvenssamhäftningen i ett OFDMsystem.I denna avhandling verifieras utförandet av olika algoritmer i olika scenariergenom simulering. Resultat visar lovande prestandaförbättringar för presenteradecc reduction detekteringsalgoritmer, till kostnaden för en acceptabelkomplexitetsökning.
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Huang, Jinliang. "Adaptation in multiple input multiple output systems with channel state information at transmitter." Licentiate thesis, Stockholm : Institutionen för elektronik, dator- och programvarusystem, Kungliga tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4443.
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Martin, Tracy A. "Analysis and simulation of disadvantaged receivers for multiple-input multiple-output communications systems." Thesis, Monterey, California. Naval Postgraduate School, 2010. http://hdl.handle.net/10945/5188.
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Approved for public release; distribution is unlimitedThis thesis investigates the simulation performance of Multiple-Input Multiple-Output (MIMO) communication systems. Uncoded narrowband and wideband MIMO systems are presented and simulated. The system is further refined with the addition of Space-Time Codes (STC) and Channel State Information at the Transmitter (CSIT). A disadvantaged receiver is subsequently introduced to the system lacking the optimization enjoyed by the native receiver. Simulation and analysis was conducted with multiple modulation schemes and antenna configurations. Rayleigh and Rician fading models are developed and simulated as the wireless channel. Receiver performance results based on MATLAB simulation are compared and presented.
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Surajudeen-Bakinde, Nazmat Toyin. "Genetic algorithms for multiple-input multiple-output and ultra wideband wireless communication systems." Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548809.
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saha, dhrubajyoti. "PLAYBACK BUFFERING AND CONTROL FOR LINEAR MULTIPLE INPUT MULTIPLE OUTPUT NETWORK CONTROL SYSTEMS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1363411715.
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Rajagopal, Ravikiran. "An algebraic view of multidimensional multiple-input multiple-output finite impulse response equalizers." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1070398845.
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Tejera, Palomares Pedro. "Principles and algorithms for transmission in multiple-input multiple-output broadband multiuser systems." kostenfrei, 2008. http://mediatum2.ub.tum.de/doc/652105/652105.pdf.
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Alamgir, Mohammed. "Different Multiple Input Multiple Output Systems." Thesis, 2003. https://vuir.vu.edu.au/268/.
Full textAbstract:
The use of multiple antennas at the transmitter as well as at the receiver can greatly improve the capacity of a wireless link when operating in a rich scattering environment. In such an arrangement all transmitting antennas radiate in the same frequency band so the overall spectral efciency becomes very high. Such a multiple antenna scheme, popularly known as Multiple Input Multiple Output (MIMO) has potential application in wireless local area networks (WLAN) and cellular micro-cells. One reason is that the WLANs and other short range wireless systems often operate in an indoor environment, which offers rich scattering. The other reason is the demand for higher data rates in cellular and WLAN systems to cater for multimedia services. Recently researchers have proposed di erent architectures for materializing the potential of the MIMO scheme. VBLAST (Vertical-Bell Labs Space Time) is a popular architecture that will play an important role in future standardizations. Furthermore, different decoding methods have been proposed for VBLAST. The SVD (Singular Value Decomposition) based system is envisioned as a highly effective MIMO technique in a TDD (Time Division Duplex) framework. Such a system operates by adapting the constellation size across different subchannels. In this work we study the VBLAST and SVD architectures and compare the perfor- mance and computing power requirement of these architectures. Also in this study a new effcient decoding method for the VBLAST architecture is proposed. The original VBLAST decoding method relies on the repetitive computation of the pseudoinverse of the channel matrix. Alternatively, there are methods based on the QR decomposi- tion, the matrix square root etc. Our new decoding method is based on a relatively less known matrix decomposition, the Polar Decomposition. The new method requires less computation and has several other advantages like the possibility of incremental updates, channel rank tracking, etc. We consider three different types of channels: IID random, slow fading and measured channels. The entire work is simulated in the MATLAB environment. The main contribution of this work includes: a comparative study and a head to head comparison of the VBLAST and SVD-based MIMO systems. The application of adaptive modulation in the SVD-based system and the introduction of a new effcient decoding method for the VBLAST system are also included. Simulation results are reported with comments and conclusions.
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Alamgir, Mohammed. "Different Multiple Input Multiple Output Systems." 2003. http://eprints.vu.edu.au/268/1/02whole.pdf.
Full textAbstract:
The use of multiple antennas at the transmitter as well as at the receiver can greatly improve the capacity of a wireless link when operating in a rich scattering environment. In such an arrangement all transmitting antennas radiate in the same frequency band so the overall spectral efciency becomes very high. Such a multiple antenna scheme, popularly known as Multiple Input Multiple Output (MIMO) has potential application in wireless local area networks (WLAN) and cellular micro-cells. One reason is that the WLANs and other short range wireless systems often operate in an indoor environment, which offers rich scattering. The other reason is the demand for higher data rates in cellular and WLAN systems to cater for multimedia services. Recently researchers have proposed di erent architectures for materializing the potential of the MIMO scheme. VBLAST (Vertical-Bell Labs Space Time) is a popular architecture that will play an important role in future standardizations. Furthermore, different decoding methods have been proposed for VBLAST. The SVD (Singular Value Decomposition) based system is envisioned as a highly effective MIMO technique in a TDD (Time Division Duplex) framework. Such a system operates by adapting the constellation size across different subchannels. In this work we study the VBLAST and SVD architectures and compare the perfor- mance and computing power requirement of these architectures. Also in this study a new effcient decoding method for the VBLAST architecture is proposed. The original VBLAST decoding method relies on the repetitive computation of the pseudoinverse of the channel matrix. Alternatively, there are methods based on the QR decomposi- tion, the matrix square root etc. Our new decoding method is based on a relatively less known matrix decomposition, the Polar Decomposition. The new method requires less computation and has several other advantages like the possibility of incremental updates, channel rank tracking, etc. We consider three different types of channels: IID random, slow fading and measured channels. The entire work is simulated in the MATLAB environment. The main contribution of this work includes: a comparative study and a head to head comparison of the VBLAST and SVD-based MIMO systems. The application of adaptive modulation in the SVD-based system and the introduction of a new effcient decoding method for the VBLAST system are also included. Simulation results are reported with comments and conclusions.
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chan, chih-chiao, and 詹智喬. "Multiple input Multiple output techniques inIEEE 802.16 standard." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/49900197675255455707.
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碩士國立雲林科技大學
電機工程系碩士班
95
IEEE 802.16 is the current standard for wireless broadband network, in which the techniques and specifications of the physical (PHY) and medium access control (MAC) layers in wireless metropolitan area networks (MAN) are defined. In this thesis, we mainly focus on the investigation of multiple input multiple output techniques in IEEE802.16 standard. Under various parameter setups in Reed-Solomon (RS) and convolutional codes and for different modulation techniques, we have performed the analysis for the single antenna transmission system and multiple antenna transmission system performance. The channel estimation and signal detection are used to mitigate the multipath fading effect and signal decode. A metropolitan area network is found to exhibit a lot of advantages. The MIMO techniques is a new generation’s wireless communication techniques. The goal of our research is to deeply survey the system through its model construction and analysis. The simulation results may provide suggestions to system constructions.
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Wu, Yueh-Hsun, and 吳岳勳. "Uncooperative-Multi-Cell Multiple-Input-Multiple-Output System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/73925213408941771174.
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碩士長庚大學
電機工程學系
99
Stable and high data throughput is prerequisite to many wireless applications in present. By using antenna arrays at both the transmitter and the receiver, MIMO system can substantially boost its spatial multiplexing gain which implies a linear increment of channel capacity proportional to the number of antennas. However, due to the various transmission environments, the MIMO system is often suffered the rank-deficient problem. For solving the problems mentioned above, in this study, we propose an innovative and practically attainable downlink system with multiple access points and multiple mobile stations each having multiple antennas, referred to as the Uncooperative-Multi-Cell Multiple-Input-Multiple-Output system. In the UMC-MIMO system, each mobile station is allowed to receive several independent data streams from multiple access points. A set of noise-subspace-based receive beamformers is employed at the MS to suppress mutual interferences among data streams from various BSs. Furthermore, the receive beamformers are implemented in an adaptive way by using the GSC structure. With this arrangement, we may have the transmit signal dimension high enough to pre-cancel the Inter-Stream-Interferences (MAI) at each transmit end. As computer simulations, the UMC-MIMO channel can be decomposed into a large number of independent subchannels which significantly increase the channel capacity.Keywords：MIMO, GSC, Interference cancellation
49
Gor, Leon. "Complexity reduction in multiple input multiple output algorithms." Thesis, 2007. https://vuir.vu.edu.au/1409/.
Full textAbstract:
Wireless communication devices are currently enjoying increasing popularity and widespread use. The constantly growing number of users, however, results in the shortage of the available spectrum. Various techniques have been proposed to increase the spectrum efficiency of wireless systems to solve the problem. Multiple Input Multiple Output (MIMO) is one solution that employs multiple antennas at the transmitter and receiver. The MIMO algorithms are usually highly complex and computationally intensive. This results in increased power consumption and reduced battery lifespan. This thesis investigates the complexity – performance trade-off of two MIMO algorithms. Space Time Block Coding (STBC) is a MIMO-based algorithm, which efficiently exploits spatial and temporal diversity. Recently, it has been specified in a number of 3G standards. However, not much attention has been paid to the implementation issues of this algorithm. One such issue, clipping of the Analog to Digital Converter (ADC) at the receiver, is described in the first part of the thesis (chapter 3). A small amount of clipping in an ADC can improve dynamic range and reduce the power consumption. However, the increased clipping distortion of the signal, can adversely affect the overall performance of the system. It will be shown in this dissertation that STBC are more sensitive to clipping, compared to the uncoded single antenna systems. Two receiver structures are considered: Direct Conversion (DC) structure, where the ADCs impose a square clipping function, and a Log-Polar structure, where ADC induces a circular clipping function. Log-Polar receivers were found to be clipping insensitive for the given target Symbol Error Rate (SER) of 1*10-3. This makes Log-Polar receivers an obvious choice for the system designers. The second part of the thesis (chapter 4) addresses the complexity problem associated with the QR decomposition algorithm, which is frequently used as a faster alternative to channel inversion in a MIMO scheme. Channel tracking can be employed with QR equalization in order to reduce the pilot overhead of a MIMO system in a non-stationary environment. QR decomposition is part of the QR equalization method and has to be performed in every instance that the channel estimate is obtained. The high rate of the QR decomposition, a computationally intensive technique, results in a high computational complexity per symbol. Some novel modifications are proposed to address this problem. Reducing the repetition rate of QR decompositions and tracking R (the upper triangular matrix) directly, while holding unitary matrix Q fixed, can significantly reduce complexity per symbol at the expense of some introduced error. Additional modification of the CORDIC algorithm (a square root- and division-free algorithm used to perform QR decomposition) results in more than 80% of computational complexity savings. Further, Minimum Mean Squared Error (MMSE) detection is applied to Least Mean Squared (LMS) based R tracking and channel tracking algorithms and then compared in complexity and performance to the Recursive Least Squares Decision Feedback Equalizer (RLS-DFE) tracking system in [1]. The R tracking scheme is shown to achieve more accurate channel estimates compared to the channel tracking scenario, but this advantage does not translate into better Bit Error Rate (BER) results due to errors on the first layer of the detector. Both LMS strategies have an inferior BER performance compared to the DFE RLS-based system of [1], and surprisingly the LMS schemes show no significant complexity improvement.
50
Gor, Leon. "Complexity reduction in multiple input multiple output algorithms." 2007. http://eprints.vu.edu.au/1409/1/gor.pdf.
Full textAbstract:
Wireless communication devices are currently enjoying increasing popularity and widespread use. The constantly growing number of users, however, results in the shortage of the available spectrum. Various techniques have been proposed to increase the spectrum efficiency of wireless systems to solve the problem. Multiple Input Multiple Output (MIMO) is one solution that employs multiple antennas at the transmitter and receiver. The MIMO algorithms are usually highly complex and computationally intensive. This results in increased power consumption and reduced battery lifespan. This thesis investigates the complexity – performance trade-off of two MIMO algorithms. Space Time Block Coding (STBC) is a MIMO-based algorithm, which efficiently exploits spatial and temporal diversity. Recently, it has been specified in a number of 3G standards. However, not much attention has been paid to the implementation issues of this algorithm. One such issue, clipping of the Analog to Digital Converter (ADC) at the receiver, is described in the first part of the thesis (chapter 3). A small amount of clipping in an ADC can improve dynamic range and reduce the power consumption. However, the increased clipping distortion of the signal, can adversely affect the overall performance of the system. It will be shown in this dissertation that STBC are more sensitive to clipping, compared to the uncoded single antenna systems. Two receiver structures are considered: Direct Conversion (DC) structure, where the ADCs impose a square clipping function, and a Log-Polar structure, where ADC induces a circular clipping function. Log-Polar receivers were found to be clipping insensitive for the given target Symbol Error Rate (SER) of 1*10-3. This makes Log-Polar receivers an obvious choice for the system designers. The second part of the thesis (chapter 4) addresses the complexity problem associated with the QR decomposition algorithm, which is frequently used as a faster alternative to channel inversion in a MIMO scheme. Channel tracking can be employed with QR equalization in order to reduce the pilot overhead of a MIMO system in a non-stationary environment. QR decomposition is part of the QR equalization method and has to be performed in every instance that the channel estimate is obtained. The high rate of the QR decomposition, a computationally intensive technique, results in a high computational complexity per symbol. Some novel modifications are proposed to address this problem. Reducing the repetition rate of QR decompositions and tracking R (the upper triangular matrix) directly, while holding unitary matrix Q fixed, can significantly reduce complexity per symbol at the expense of some introduced error. Additional modification of the CORDIC algorithm (a square root- and division-free algorithm used to perform QR decomposition) results in more than 80% of computational complexity savings. Further, Minimum Mean Squared Error (MMSE) detection is applied to Least Mean Squared (LMS) based R tracking and channel tracking algorithms and then compared in complexity and performance to the Recursive Least Squares Decision Feedback Equalizer (RLS-DFE) tracking system in [1]. The R tracking scheme is shown to achieve more accurate channel estimates compared to the channel tracking scenario, but this advantage does not translate into better Bit Error Rate (BER) results due to errors on the first layer of the detector. Both LMS strategies have an inferior BER performance compared to the DFE RLS-based system of [1], and surprisingly the LMS schemes show no significant complexity improvement.